Avison



lit with reference to the drawings.

@ui-teh.' guttersv getint' @ffirew F. Im v I s o-N, or R Ion M oL No, vI RG'I'N 1 i.

i entrapment lvm 75,872, sans March 24, 186s.

. finesor'susnr rNcir-Hs-oHoss-- die Situatie-ritenettr "influssi:ttters ate'nt mit untingpart aitigt sanc 'ro VALL wHoM 1T MAY concluante Be itI lmown thet I, F. Dsvrsor r, ofeltiehmond, in Athe county ofHenrico, and State et' Virginia, have invented n new and usefulIinprovenxent in Chucks; und do hereby dsolsrethat the Vullowiig isa.full, clear, and exnet description of the same, reference being' had'tothe eeeouipsnying drnwing's,`making a. portion of this specification,in wl1iehl i Figurel 'is a .transverse section of a ehuelimadeaccrdingto my invention. 4 Fi( e2is a bach vieuP of thersnmel. i

-Similar letters of reference indicatefcorrospending 'parts in bothfigures. This invention consists in a shell, furnished with appropriatoholding-jaws, a slotted disk or fece-plete, end a tightening-sc'revgnocombined 'that the chuck muy be employed with very'grcat convenience,either for eccentrioor'concontric turning, as occasion may' require. ATo-ennble others to understandl the construction and' operntion of myinvention, I will proceed to descrzihe A represents a circular shell',4pxovidedivfith a centrer opening' ctv-a, und havingv radialguides orrecesses formed in it, in whieh'ore situated the. sliding'holdingfjowsB, the outer ends oil-'which project beyond the front surface of theshell, as shown in figli, passing inwurd through the circular sides dfthe shell.4 In positions radial to the nxis of such shell are screws b,`whieh pns's through feniale screws provided in thc jaws B, and are eachvfurnished with a. bevel-pinion, e, which gears with a bevel or toothedrim,` C, situated in a suitable annular guide ut the inner pin-t of` thoshell, as indicated in ti-g. 1, in such manner-that,'by turning one `ofthe screws b in' one direction or the otheryb'y means ofia wrench, orother suitabl'emenns applied to its head or outferl extremity, it Vwillnot only move inward or outward, as thecase-may be, the holding-jaw B,through which it is passed, but' also, by means of the pinions e and rimC, willopcrate the remaining screws b, to simnltaneouslymove theotherjaws in n corresponding direction, either to hold the article heldbetween the concentric jaws, or to] rele-isc it therefrom, as oecesionmuy require. 4Shown ntf D is a disk enfado-plate, formed with ncenttalfeniele screw` at c, wllerebyit may be attached to the mandrel ofthe lathe: The shell is pivoted by a pivot,';f. "Tothe front of thisface-plate, :tt n. greater or less distance from thecentro of theface-pluto, as represented initho figures,

n'nd formed in the opposite side of 'theface-plntc, is anfora-shapedslot, g, concentric to the'pivot f, and through Vwhich is' passedabroadrhecded scieiv, m, which 'scrcu's linto'thcv hach ofvthe shell A'insuch manner that, by turning the screw to tigliton the head thereofYagainst those portions of .the disk n'djacent to the slot m, t-hc shellwill be firmly held to' thc face-plate, either inA o. positincorresponding with that ofthe disk, or eccentric thereto', :is indicatedb'y the red outline inig. 2, the slot m enabling the shell to beadjusted with'itscentreat'any desired' distance from that of theface-pluto, so that unydcsirod degree of occentricityof t'heholdingejaws of the shell, with reference to the centre of theface-plnte,ot,` in other words, with the'nxis ofniotion of the chucls`when the chuck is us'ed,'muy be secured, this adjustuhility ofthe shell,whielrcarries the holding-jaws upon'the face-plete;l vfitting the chuckfor usc either in once'ntricoreccentric turning, as tney be, requied. i

What I claim as my invention, and desire to secure by Letters Patent, isl The combination oi' the pivoted shell, provided 4ivith holding-jaws,'the slotted disk o r face-plate, and the tightening-screw,substantially as and for the' purpose specified. l DAVISON. Witnesses J.Pennant., T. D. ALLEN

